After I install the plug-in to the standard directory and activate it I see the following error message repeated 6 times at the top of the Manage/Write Post admin page:
Warning: in_array() [function.in-array]: Wrong datatype for second argument in /home/********/public_html/******************/****/wordpress/wp-content/plugins/wp-existing-tags/wp-extags.php on line 77
Thanks in advance for any assistance.